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A098897
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Palindromic deficient numbers.
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2
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1, 2, 3, 4, 5, 7, 8, 9, 11, 22, 33, 44, 55, 77, 99, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 202, 212, 232, 242, 262, 292, 303, 313, 323, 333, 343, 353, 363, 373, 383, 393, 404, 424, 434, 454, 484, 494, 505, 515, 525, 535, 545, 555, 565, 575, 585, 595
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(10)=22 because 22 is the tenth deficient number which is palindromic also.
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MATHEMATICA
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Select[Range@ 900, And[DivisorSigma[1, #] < 2 #, PalindromeQ@ #] &] (* Michael De Vlieger, Nov 08 2017 *)
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PROG
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(PARI) isok(n) = (sigma(n) < 2*n) && (d=digits(n)) && (Vecrev(d) == d); \\ Michel Marcus, Nov 08 2017
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CROSSREFS
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KEYWORD
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easy,nonn,base
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AUTHOR
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STATUS
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approved
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